Data writer with tapered side shield sidewalls

ABSTRACT

A data writer may be generally configured at least with a write pole that has a pole sidewall and a continuous first taper angle connecting leading and trailing edges. The write pole can be positioned adjacent to a side shield that is configured with first and second shield sidewalls tapered to a shield tip that is the closest point between the write pole and side shield.

RELATED APPLICATION

This application is a continuation of copending U.S. patent applicationSer. No. 13/689,337 filed on Nov. 29, 2012 which will issue on Sep. 9,2014 as U.S. Pat. No. 8,830,625.

SUMMARY

Various embodiments are generally directed to a data writer capable ofbeing used in high data bit density data storage environments.

In accordance with various embodiments, a write pole may have a polesidewall and a continuous first taper angle connecting leading andtrailing edges. The write pole may be positioned adjacent to a sideshield that is configured with first and second shield sidewalls taperedto a shield tip that is the closest point between the write pole andside shield.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view block representation of an example data storagedevice constructed and operated in accordance with various embodiments.

FIG. 2 illustrates a cross-sectional block representation of an examplemagnetic element capable of being used in the data storage device ofFIG. 1.

FIG. 3 shows an ABS view block representation of a portion of an examplemagnetic element constructed in accordance with some embodiments.

FIG. 4 displays an ABS view block representation of a portion of anexample magnetic element constructed in accordance with variousembodiments.

FIG. 5 illustrates an ABS view block representation of a portion of anexample magnetic element constructed in accordance with variousembodiments.

FIG. 6 is an ABS view block representation of a portion of an examplemagnetic element constructed in accordance with some embodiments.

FIG. 7 provides a flowchart for an example magnetic element fabricationroutine conducted in accordance with various embodiments.

DETAILED DESCRIPTION

As data storage devices advance towards greater data storage capacityand faster data access rates, magnetic shielding of errant magnetic fluxhas become an acute source of manufacturing and operational performancedifficulties as the physical size and tolerances of various devicecomponents is reduced. While the minimization of data tracks on whichdata bits populate can pose a particular operational difficulty in theform of adjacent track interference (ATI), positioning lateral magneticshields adjacent a magnetic access feature, such as a write pole andmagnetoresistive lamination, may mitigate ATI by reducing the magneticextent of the access feature. However, the addition of lateral magneticshields can suffer from magnetic field and magnetic gradient loss as themagnetic shields saturate with magnetization intended for the magneticaccess feature. Hence, there is a continued industry demand for magneticshield configurations capable of being implemented in reduced formfactor data storage devices without decreasing magnetic field andgradient.

Accordingly, various embodiments can generally be directed toconfiguring a magnetic element with a write pole having a pole sidewalland a continuous first taper angle connecting leading and trailingedges, where the write pole is positioned adjacent a side shield that isconfigured with first and second shield sidewalls tapered to a shieldtip that is the closest point between the write pole and side shield.The position of the shield tip and the angular orientation of the shieldsidewalls from the shield tip in relation to the write pole can beselectively tuned to provide a predetermined magnetic extent. Such tunedmagnetic shield configurations can additionally mitigate magnetic fluxsaturating the shields instead of contributing to data bit access.

While at least one tuned magnetic shield may be practiced in anunlimited variety of environments, FIG. 1 generally illustrates a topview block representation of an example data storage device 100 that canutilize a tuned magnetic element in accordance with various embodiments.The data storage device 100 is shown in a non-limiting configurationwhere an actuating assembly 102 is capable of positioning a transducinghead 104 over a variety of locations on a magnetic storage media 106where stored data bits 108 are located on predetermined data tracks 110.The storage media 106 can be attached to one or more spindle motors 112that rotate during use to produce an air bearing surface (ABS) on whicha slider portion 114 of the actuating assembly 102 flies to position ahead gimbal assembly (HGA) 116, which includes the transducing head 104,over a predetermined portion of the media 106.

The transducing head 104 can be configured with one or more transducingelements, such as a magnetic writer, magnetically responsive reader, andmagnetic shields, which operate to program and read data from theselected data tracks 110 of the storage media 106, respectively. In thisway, controlled motion of the actuating assembly 102 correspond withalignment of the transducers with the data tracks 110 defined on thestorage media surfaces to write, read, and rewrite data. As data bits108 become more densely positioned in data tracks 110 with smallerradial widths, the head 104 may inadvertently receive magnetic flux fromdata bits on adjacent data tracks 110, which can induce magnetic noiseand interference that degrades performance of the data storage device100.

FIG. 2 displays a cross-sectional block representation of an examplemagnetic element 120 constructed with magnetic shielding to mitigate theeffects of reduced form factor data tracks and more densely packed databits. As shown, the magnetic element 120 can comprise have one or moredata access elements, such as the magnetic reader 122 and writer 124,which can operate individually or concurrently to write data to orretrieve data from an adjacent storage media, such as media 106 ofFIG. 1. Each magnetic element 122 and 124 is constructed of a variety ofshields and a transducing element that act to read data from and writedata to a corresponding data medium along a data track 126.

The magnetic reading element 122 has a magnetoresistive layer 130disposed between leading and trailing shields 132 and 134. Meanwhile,the writing element 124 has a write pole 136 and at least one returnpole 138 that creates a writing circuit to impart a predeterminedmagnetic orientation to the adjacent storage media. In the non-limitingconfiguration of the write element 124 shown in FIG. 2, two return poles138 are each contactingly adjacent a non-magnetic gap layer 140 andtrailing shield 142, respectively, that prevent flux from the poles 136and 138 from extending beyond the bounds of the writing element 124.Each return pole 138 further contacts insulating material 144 thatmaintains magnetic separation of the writing poles 136 and 138.

The shields of the magnetic element 120 can be characterized by theirposition with respect to the timing of encountering external bits, suchas bits 108 of FIG. 1. In other words, the shields that encounter theexternal bits before the transducing elements 122 and 124 are “leading”shields while shields that see the bits after the transducing elementsare “trailing” shields. Such characterization extends to the differencebetween “uptrack” or “downtrack” of the transducing elements in that,depending on the direction of travel for the magnetic element 120 andexternal bits, the shields can be either leading or trailing and eitheruptrack or downtrack.

While the magnetic element 120 has a plurality of shielding layerspositioned along the Y axis that dispel magnetic flux from reachinguptrack and downtrack magnetic bits, increased data bit densities haveled to the tighter data tracks 126 that correspond with additionalshielding along the Z axis. The addition of side shields in the Z axisin relation to the write pole 136 can cater the magnetic extent of thewrite pole 136 to conform to a reduced data track 126 width, but suchaddition can decrease magnetic field amplitude and gradient asmagnetization saturates the side shields instead of flowing through thewrite pole. The reduction in magnetic field can operationally reduce themagnetic sensitivity and data programming efficiency of the write pole136, which can result in degraded linear data bit density capacity andincreased the chances of side track erasure as the write poleinadvertently programs data bits of adjacent data tracks 126.

FIG. 3 provides an ABS view block representation of a portion of anexample magnetic element 150 employing tuned side shields 152 onopposite sides of a write pole 154 in accordance with variousembodiments. Each side shield 152 is configured with first 156 andsecond 158 shield sidewalls that taper to a shield tip 160 while thewrite pole 154 has pole sidewalls 162 that taper to a pole tip 164positioned uptrack from a pole body 166. It is to be understood thatFIG. 3 is generally illustrated as aligned with a predetermined trackwhere the bottom portion of the magnetic element 150 is uptrack and willencounter a data bit before a downtrack portion at the top plane of theelement 150.

Configuring the side shields 152 with a uniform write gap 168 from thepole body 166 to the pole tip 164 by configuring the shield sidewall 158angle (Θ₁) to match the pole sidewall 162 angle (Θ₂) can providecontrolled magnetic extent for the write pole 154, but may provide aconduit for magnetic flux to saturate the side shields 152 instead ofbeing transmitted through the write pole 154. With such magneticconcerns in mind, one or more side shield 152 can be constructed, asshown, so that the shield tip 160 is the closest point between the writepole 154 and the side shield 152. The ability to tune the verticalposition of the shield tip 160 along the Y axis and the taper angles (Θ₁& Θ₃) of the respective shield sidewalls 156 and 158 can control themagnetic extent of the write pole 154 without providing easy magneticconduits between the write pole 154 and the side shields 152.

As a non-limiting example, each side shield 152 may be configured sothat the shield tip 160 is positioned between the pole tip 164, whichcan be characterized as the leading edge, and the pole body 166, whichcan be characterized as the trailing edge, and the shield sidewalls 156and 158 respectively extend in different directions and angles (Θ₁ & Θ₃)from the shield tip 160 so that the distance 170 from the pole sidewall162 to the shield tip 160 is smaller than either distance 172 and 174from the pole sidewall 162 to the first 156 or second 158 shieldsidewall. Various embodiments tune the distance 174 to be twice thedistance 170 and greater than distance 172 to configure the magneticextent of the write pole 154 to reduce both side track erasure andadjacent track interference.

The presence of fringe magnetic fields proximal the pole tip 164 cancontribute to inadvertent programming of adjacent data tracks in a sidetrack erasure condition. Such condition may be mitigated at least byadjusting the length of the shield sidewalls 156 to extend uptrack fromthe pole tip 164 a predetermined distance 176, which may be greater thana predetermined width 178 of the pole body 166 at plane 180. With thewide variety of tunable magnetic element characteristics like the taperangles (Θ₁, Θ₂, & Θ₃) of the shield 156, 158 and pole sidewalls 162 aswell as the position of the shield tip 160, the magnetic extent of thewrite pole 154 can be manipulated into a number of different shapes thatcan increase data writing performance, especially in reduced formfactor, high data bit density storage devices.

FIG. 4 illustrates an ABS view block representation of a portion of anexample magnetic element 190 tuned with a variety of structural featuresin accordance with some embodiments. The magnetic element 190 has awrite pole 192 disposed between side shields 194 and a trailing shield196 each configured with magnetic extent altering features such asletterbox 198, shield sidewalls 200 and 202, and pole sidewalls 204. Thewrite pole 192 is configured with a linear trailing edge 204 and curvedleading edge pole tip 206 between which a shield tip 208 is positionedand the shield sidewalls 200 and 202 extend therefrom with lengths thattake each sidewall 200 and 202 beyond the bounds of the leading 206 andtrailing 204 edges.

As with the shield and pole sidewalls of FIG. 3, the various sidewalls200, 202, and 204 can be tuned to an unlimited variety of angles (Θ₁,Θ₂, & Θ₃) that allow different shield-to-pole distances at the leadingedge 206, trailing edge 204, and shield tip 208. Regardless of the tunedangles of the various sidewalls and size of the gap between the sideshield 194 and write pole 192, the inclusion of a letterbox 198downtrack from the write pole 192 can provide adequate magneticshielding while minimizing magnetic flux loss from the pole 192, whichincreases write field gradient, amplitude, and gain. The letterbox 198is displayed as being formed partially out of the side 194 and trailing196 shields, but such configuration can be altered, at will, to whollyincorporate the letterbox as part of either the side 194 or trailing 196shields.

The position and shape of the letterbox 198 may be tuned in variousembodiments to provide a balance between magnetic shielding and writefield gain and gradient of the write pole 192. That is, the width 210and distance 212 from the write pole 198 may be tuned, along with theoverall shape such as continuously curvilinear and rectangular, toprovide predetermined shielding and magnetic performance characteristicsfor the write pole 192. The addition of a tuned letterbox 198 can reducemagnetic overshoot as stray fields are reduced at least by shapeanisotropy provided by the tuned shield sidewalls 200 and 202 having thelongest sidewall closest to the write pole 192. The letterbox 198 may becomplemented by the tuned position of the shield tip 208 provided byleading 214 and trailing 216 distance of the shield tip 208 from therespective leading 206 and trailing 204 edges of the write pole 192 toreduce side track erasure and increase magnetic transition curvature.

While the configurations of the side shields 194, write pole 192, andletterbox 198 can position shielding material in predetermined proximityto selected portions of the write pole 192 and allow magneticallyinsulating material to be disposed between the shields 194 and 196 andthe write pole 192, the various magnetic element 190 components mayfurther be tuned for shape, material, size, and position to manipulatethe magnetic extent of the write pole 192 while providing optimizedmagnetic write fields. FIG. 5 generally displays an ABS view blockrepresentation of a portion of an example magnetic element 220 tuned inaccordance with various embodiments. The magnetic element 220 has awrite pole 222 disposed between side shields 224 that are each tuned toprovide more than two shield sidewalls.

As shown, the write pole 222 has a substantially trapezoidal shape withopposite facing pole sidewalls 226 connecting leading 228 and trialing230 edges. Each side shield 224 is configured with first 232 and second234 shield sidewalls tapering at predetermined angles from a shield tip236 consisting of a tip sidewall 238. In comparison to the shield tip208 of FIG. 4, the shield tip 236 is not the meeting point of twosurfaces but instead a surface having a predetermined length 240connecting the other shield sidewalls 232 and 234. The use of a linearsurface for the tip sidewall 238, or alternatively a continuouslycurvilinear surface in some embodiments, provides another tunablestructural surface that allows the write gap between the write pole 222and side shields 224 to vary at predetermined distances 242 and 244 inrelation to the pole sidewall 226.

The shape and position of the tip sidewall 238 can allow the first 232and second 234 shield sidewalls to taper and extend at angles that wouldbring the shield sidewalls too close to the write pole 222 if the shieldsidewalls 232 and 234 met at a point. For example, the length of the tipsidewall 238 may allow the second shield sidewall to extend from theshield tip 236 at a lesser angle to provide a predetermined distance tothe trailing edge 230 of the write pole 222 than if the length 240 ofthe tip sidewall 238 were not present. Such lesser shield sidewallangles may be utilized, in some embodiments, to form a predeterminedside shield width 246 a predetermined downtrack distance 248 from thewrite pole 222, which can create letterbox-type write field gain andgradient optimization without the additional manufacturing of aletterbox into the side 224 and/or trailing shields.

The wide variety of shielding configurations possible by tuning thevarious shield and pole sidewalls are not limited to mirroringstructures on opposite sides of the write pole 222. FIG. 6 generallyillustrates how an example magnetic element 260 can be tuned to controlthe magnetic extent of a write pole 262 with differing side shield 264and 266 configurations constructed in accordance with some embodiments.The ABS view of the magnetic element 260 displays a first side shield264 constructed as a lamination of multiple different materials havingdifferent magnetic shielding characteristics and structuralorientations.

In the example shown in FIG. 6, the first side shield 264 has first 268,second 270, and third 272 shield layers each having differentthicknesses 274, 276, and 278 along the Y axis and different shieldsidewalls 280, 282, and 284 oriented with different angles (Θ₁ & Θ₂)with respect to the pole sidewall 286 (Θ₃). Some embodiments configurethe shield sidewalls 280, 282, and 284 to provide a leading distance 288between the side shield 264 and the leading edge of the write pole 262that is half a trailing distance 290 between the side shield 264 and thetrailing edge of the write pole 262. Configuring the leading distance288 as half the trailing distance 290 can provide write field optimizedfor minimum adjacent track interference.

The increasing write gap between the first side shield 264 and writepole 262 can be complemented by the use of materials exhibitingdifferent magnet moments. For example, the first layer 268 can beconstructed with a first predetermined moment, such as 2.4 Tesla, whilethe second layer 270 has a different second predetermined moment, suchas 1.4 Tesla, and the third layer 272 is configured with a differentthird predetermined moment, such as 1.0 Tesla. The varying magneticmoments of the different layers 268, 270, and 272 can minimize writefield loss as stray magnetic fields are controlled, particularlyproximal to the leading pole tip 292. The ability to tune the size,position relative to the write pole 262, and material of the variousside shield 264 lamination provides additional tuning aspects that canallow precise articulation of the magnetic extent and magneticcharacteristics of the write pole 262.

While the use of multiple different shield layers 268, 270, and 272 andmaterials can provide precise tuning capabilities, additionalmanufacturing complexity and processing may counteract the effects ofthe laminated side shield configuration. The second side shield 266displays how a single layer and material can be constructed with aplurality of shield sidewalls 294, 296, 298, and 300 constructed withdifferent angular orientations (Θ₄, Θ₅, Θ₆, & Θ₇) to produce a shieldtip 302 that is the closest point between the write pole 262 and thesecond side shield 266.

The position of the shield tip 302 may be positioned proximal to anypredetermined portion of the pole sidewall 286, but such predeterminedportion may be more towards the trailing portion of the write pole 262when the side shield extends a plane downtrack from the leading pole tip292. That is, the position of the shield tip 302 may be chosen inresponse to the downtrack distance 304 the side shield 266 extends. Suchdowntrack distance 304 may further alter the leading 306, tip 308, andtrailing 310 distances to balance magnetic shielding with write fieldgain and gradient to provide predetermined adjacent track interferenceand side track erasure mitigation.

With the variety of non-limiting side shield configurations possible tooptimize write field and data bit programming performance, theconstruction of a magnetic element can undergo a series of general andspecific decisions to tune the magnetic operation. FIG. 7 provides anexample magnetic element fabrication routine 330 conducted in accordancewith various embodiments to tune the magnetic shielding and magneticwrite field performance of a magnetic element. Initially, routine 330constructs a write pole with a predetermined shape, sidewalls, and poletip in step 332.

Decision 334 determines whether or not one, or both, side shields are tobe constructed as a multi-layer lamination. If a plurality of differentside shield layers are to be utilized from decision 334, step 336successively forms each side shield layer with predetermined materials,thicknesses, and shield sidewall angular orientations. In contrast, step338 deposits a single side shield layer and forms a shield tip with apredetermined number of shield sidewalls extending therefrom. Variousembodiments configure the shield sidewalls to extend beyond the leadingand trailing edges of the write pole with other embodiments position theshield tip proximal a predetermined portion of the write pole, such as10%, 30%, or 50% of the length of the pole sidewall from the leadingedge.

It should be noted that the formation of side shields on opposite sidesof the write pole can be accomplished through performing either steps336 and 338 once, or multiple times. The formation of side shields onopposing sides of the write pole advances the routine 330 to decision340 where the inclusion of letterbox, such as letterbox 198 of FIG. 4,is contemplated. Step 342 forms a letterbox that has a predeterminedshape, such as rectangular, trapezoidal, and rectangular shapes, apredetermined size, and a predetermined distance from the write pole.Such letterbox construction may incorporate the processing of one, orboth, side shields and a trailing shield that is subsequently depositedin step 344. That is, a letterbox may be wholly incorporated into theside or trailing shields or made up of a combination of surfacesprovided by both the side and trailing shields.

In the event a letterbox is not to be incorporated into the magneticelement in decision 340, step 344 deposits the trailing shield apredetermined distance from the write pole without forming an internalletterbox opening. Through the various decisions and steps of routine330, a magnetic element can be optimized for performance by balancingmagnetic shielding with write field performance through tunedconfigurations of the various side shield sidewalls, distances, andshield tip positions. For example, the tapered shield sidewalls andposition of the shield tip can be configured in a variety of positionsrelative to the write pole to provide more, or less, magnetic shieldingcombined with decreased, or minimized, risk of inadvertent performancecharacteristics, such as side track erasure and adjacent trackinterference.

It should be noted, however, that the various steps and decisions ofroutine 330 shown in FIG. 7 are not required or limited as the variousdecisions and steps can be omitted, changed, and added. As an example,decision 334 and steps 336 and 338 can be performed multiple times withsimilar or different results to construct side shields positioned onopposite sides of the write pole.

The plethora of side shield structural parameters that can be tuned toprovide predetermined magnetic shielding and data bit programmingperformance illustrates the vast possible side shield configurationscapable of controlling the magnetic extent of a write pole. Such sideshield configurations may be tuned to provide heightened magnetic fieldperformance with optimized write field gain and gradient while otherconfigurations may be tuned to minimize inadvertent performanceconditions resulting from errant magnetic fields and magnetic saturationof the side shields. The ability to balance these various performancecharacteristics by tuning the various structural aspects of the sideshields with respect to the write pole conveys the versatility of sideshield construction, especially in regard to adapting to increased databit density, reduced form factor data storage devices.

In addition, while the embodiments have been directed to magneticprogramming, it will be appreciated that the claimed invention canreadily be utilized in any number of other applications, including datastorage device applications. It is to be understood that even thoughnumerous characteristics and configurations of various embodiments ofthe present disclosure have been set forth in the foregoing description,together with details of the structure and function of variousembodiments, this detailed description is illustrative only, and changesmay be made in detail, especially in matters of structure andarrangements of parts within the principles of the present disclosure tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed. For example, the particularelements may vary depending on the particular application withoutdeparting from the spirit and scope of the present technology.

What is claimed is:
 1. An apparatus comprising a write pole disposedbetween first and second side shields on an air bearing surface (ABS),the write pole and side shields being symmetrical about a longitudinalaxis of the write pole bisecting trailing and leading edges of the writepole, each side shield comprising first, second, and third shieldsidewalls, the first and second side shield sidewalls angled withrespect to a write pole sidewall to meet at a shield tip, the shield tiporiented parallel to the longitudinal axis and positioned between theleading and trailing edges of the write pole proximal the write polesidewall on the ABS.
 2. The apparatus of claim 1, wherein the write polehas a pole length on the ABS between the leading and trailing edgesalong the longitudinal axis, the shield tip positioned within the polelength.
 3. The apparatus of claim 1, wherein the first and second shieldsidewalls are angled at different angles with respect to one another. 4.The apparatus of claim 1, wherein the first shield sidewall of each sideshield continuously extends uptrack from the leading edge of the writepole.
 5. The apparatus of claim 1, wherein the second shield sidewall ofeach side shield continuously extends downtrack from the trailing edgeof the write pole.
 6. The apparatus of claim 1, wherein the shield tipis the closest point between the write pole and the respective first andsecond side shields.
 7. The apparatus of claim 1, wherein the first andsecond shield sidewalls extend in opposite directions from the shieldtip.
 8. The apparatus of claim 1, wherein the shield tip is closer tothe leading tip than the trailing edge of the write pole.
 9. Theapparatus of claim 1, wherein the third side shield sidewall iscontinuously linear and oriented at a different angle, relative to thewrite pole sidewall, than the first or second side shield sidewalls. 10.An apparatus comprising a write pole disposed between first and secondside shields on an air bearing surface (ABS), the write pole and sideshields being symmetrical about a longitudinal axis of the write polebisecting trailing and leading edges of the write pole, each side shieldcomprising first, second, and third shield sidewalls angled with respectto a write pole sidewall to meet at a shield tip, the shield tipcomprising the third shield sidewall oriented parallel to thelongitudinal axis of the write pole and positioned between the leadingand trailing edges of the write pole proximal the write pole sidewall onthe ABS.
 11. The apparatus of claim 10, wherein the tip third shieldsidewall has a length along the longitudinal axis that is less than alength of the write pole sidewall, as measured along the longitudinalaxis.
 12. The apparatus of claim 10, wherein the first and second shieldsidewalls extend in opposite directions from the third shield sidewallat a common angular orientation with respect to the third shieldsidewall.
 13. The apparatus of claim 10, wherein the tip third shieldsidewall is positioned downtrack of the leading edge of the write poleand uptrack of the trailing edge of the write pole.
 14. The apparatus ofclaim 10, wherein a leading point of the third shield sidewall isfarther away from the write pole than a trailing point, the leading andtrialing points aligned along the longitudinal axis.